Discover insights from thousands of peer-reviewed papers on microbial electrochemical systems
Abdelkader Hilmi, Timothy Geary, Adam Franco et al.
ECS Meeting Abstracts · 2023
Introduction The molten carbonate fuel cell (MCFC) has emerged as one of the promising alternatives for carbon capture from industrial and power generation CO 2 sources. MCFC technology is less energy-intensive compared to conventional amine scrubbing that requires a significant amount of energy (steam) for solvent regeneration process. MCFC has been commercially used for distributed power generation, however its use in carbon capture applications has been limited to development activities and a few demonstrations during the past decades. The electrochemical reactions taking place during cell operation involve the CO 2 transfer from cathode to anode in the form of carbonate ions resulting in a gas stream with high CO 2 concentration on the anode exhaust. Therefore, MCFC stack systems can be combined with conventional combustion-powered generators (coal and/or natural gas-based power plants) for simultaneous CO 2 separation, power and hydrogen generation. CO 2 capture applications will typically take in flue gas from industrial furnaces, coal and gas fired combined cycle plants as the cathode inlet gas stream having low CO 2 concentrations ranging from 4% to 10% by volume and high CO 2 utilization (>90%). These CO 2 -lean conditions may pose a challenge for attaining good mass-transfer performance and life stability, therefore innovative approaches are needed in terms of hardware design and cathode structure to achieve long-term stability. FCE has tested numerous single cells (250 cm 2 ) and technology stacks (30 kW) under carbon capture operating conditions (4-8% CO 2 in the cathode inlet as opposed to >12% in baseline MCFC systems) to understand impact of design parameters on performance, life, and to investigate design solutions for further enhancement. Figure 1 highlights the effect of cathode water content on CO 2 utilization. It appears that differences exist between the ideal and measured CO 2 utilizations, indicating that less CO 2 is transferring from the cathode to anode than expected. This CO 2 transference reduction becomes more pronounced with higher water concentration, suggesting that a species other than CO 3 2- ion, likely hydroxide (OH - ion), may be generated and transported through the electrolyte matrix. This paper will review the cathode material stability and electrochemical performance under long-term carbon-capture operation. The effect of parameters such as water content, gas composition, utilization, and electrolyte chemistry, as well as approaches to enhance the CO 2 capture efficiency and life, will be discussed. Figure 1
Samuel Simon Araya, Søren Juhl Andreasen, Søren Knudsen Kær
Journal of Fuel Cell Science and Technology · 2014
As fuel cells are increasingly commercialized for various applications, harmonized and industry-relevant test procedures are necessary to benchmark tests and to ensure comparability of stack performance results from different parties. This paper reports the results of parametric sensitivity tests performed based on test procedures proposed by a European project, StackTest. The sensitivity of a Nafion®-based low temperature PEMFC stack's performance to parametric changes was the main objective of the tests. Four crucial parameters for fuel cell operation were chosen; relative humidity (RH), temperature, pressure, and stoichiometry at varying current density. Furthermore, procedures for polarization curve recording were also tested both in ascending and descending current directions.
Takuya Tsujiguchi, Misaki Kojima, Takanori Iwakami et al.
ECS Transactions · 2013
A hyperbranched polymer was used as a catalyst stabilizer for use in a direct formic acid fuel cell, DFAFC, to obtain a high performance with a low catalyst loading. The catalyst ink was prepared by the mixing of Pd nanoparticles stabilized by a hyper branched polymer (H-Pd) and carbon black, which was then calcinated at 300 oC and 500 oC in flowing nitrogen to investigate the effect of the stabilizer residual on the catalytic activity for the formic acid oxidation. It was found that the catalytic activity of the H-Pd was 6 times higher than that of Pd black with a 500 oC calcination. In this condition, a cluster of Pd nanoparticles was observed. By using this catalyst as an anode catalyst of the DFAFC, a 6 times higher power density could be obtained compared to the case using Pd black.
Scott A Mauger, Min Wang, Samantha Medina et al.
ECS Meeting Abstracts · 2019
Industrial production of polymer electrolyte membrane fuel cell (PEMFC) electrodes will rely on continuous roll-to-roll (R2R) coating methods to meet the rates needed for mass production. 1–5 R2R production commonly uses solution coating methods to coat liquids onto a moving substrate at linear speeds over 100 m/min. 6 There are many coating methods, which have different coating physics and require different ink formulations. For PEMFC catalyst layers these differences may result in different morphologies and performance. As production of fuel cell vehicles and power systems increases there is a need to understand the process science of fuel cell manufacturing. Here we present the results of a study comparing fuel cell catalyst layers coated using two R2R coating methods: slot-die and gravure, shown in Figure 1. These two methods were selected because the physics of applying the liquid to the substrate is very different between the two cases. Also, they have different viscosity and wet-film thickness ranges, which may make one method better suited to certain materials or catalyst loadings. In slot die coating, the pre-metered liquid is fed through the cavity of a metal die and extruded onto the substrate, as shown in Figure 1a. In gravure coating, an engraved metal roller is used to transfer the liquid from a pan to the substrate (Figure 1b). In both of these methods the coated liquid film then consolidates into the final dry film. These methods are quite different than common lab-scale coating methods like ultrasonic spraying or hand painting where ink is repeatedly applied to the same area to build up the thickness of the catalyst layers. Pt/C catalysts layers were coated directly onto carbon-fiber gas diffusion media to create gas diffusion electrodes (GDEs), without the use of a decal transfer process. These GDEs were assembled into membrane electrode assemblies (MEAs) by hot pressing to Nafion membranes. In situ performance and other electrochemical diagnostics were used to determine the influence of coating method on catalyst layer electrochemical properties. Electron microscopy was utilized to understand the influence of coating method on electrode morphology and its influence on electrochemical properties. We also explored the influence of solvent ratio to understand the potential coupling between ink formulation and coating methodology. Through this work we demonstrate R2R-coated GDEs with performance equal to ultrasonic spray-coated GDEs and a 200x increase in production rate. This demonstrates that R2R coating methods are suitable for mass-production of high-performance fuel cells. It also lays a foundation for further process science studies. (1) Mauger, S. A.; Neyerlin, K. C.; Yang-Neyerlin, A. C.; More, K. L.; Ulsh, M. Gravure Coating for Roll-to-Roll Manufacturing of Proton-Exchange-Membrane Fuel Cell Catalyst Layer. J Electrochem Soc 2018 , 165 (11), F1012–F1018. https://doi.org/10.1149/2.0091813jes. (2) Bodner, M.; García, H. R.; Steenberg, T.; Terkelsen, C.; Alfaro, S. M.; Avcioglu, G. S.; Vassiliev, A.; Primdahl, S.; Hjuler, H. A. Enabling Industrial Production of Electrodes by Use of Slot-Die Coating for HT-PEM Fuel Cells. Int. J. Hydrog. Energy 2019 . https://doi.org/10.1016/j.ijhydene.2018.11.091. (3) Steenberg, T.; Hjuler, H. A.; Terkelsen, C.; Sánchez, M. T. R.; Cleemann, L. N.; Krebs, F. C. Roll-to-Roll Coated PBI Membranes for High Temperature PEM Fuel Cells. Energy Environ. Sci. 2012 , 5 (3), 6076–6080. https://doi.org/10.1039/c2ee02936g. (4) Ding, X.; Didari, S.; Fuller, T. F.; Harris, T. A. A New Fabrication Technique to Manufacture an MEA Using Direct Coating of Nafion® onto Catalyzed GDL. In 218th ECS Meeting ; ECS, 2010; pp 255–265. https://doi.org/10.1149/1.3484523. (5) Ding, X.; Didari, S.; Fuller, T. F.; Harris, T. A. L. Membrane Electrode Assembly Fabrication Process for Directly Coating Catalyzed Gas Diffusion Layers. J. Electrochem. Soc. 2012 , 159 (6), B746. https://doi.org/10.1149/2.103206jes. (6) Ding, X.; Liu, J.; Harris, T. A. L. A Review of the Operating Limits in Slot Die Coating Processes. AIChE J. 2016 , 62 (7), 2508–2524. https://doi.org/10.1002/aic.15268. Figure 1
Antonio Molinero, Juan Carlos Oller, José Miguel Barcala et al.
ECS Meeting Abstracts · 2022
An airship, or dirigible balloon, is an aircraft that gains its lift from a gas less dense than air, like helium. For traction, airships have two or more propellers normally attached to a gondola that is suspended under the balloon. At present, they are used for hovering long times without the need for a high speed, like for aerial observation, advertising, or as camera platforms. In our laboratory, the airship is being used as a platform for testing hydrogen fuel cell systems for aerial applications. The airship used in this communication is a 3 m 3 polyurethane's inflatable zeppelin, with radio control, and three electrical propellers (Fig. 1a). A hydrogen fuel cell system has been developed and integrated with the gondola for powering the propellers and electronics. The fuel cell is a 15 W PEMFC stack prototype able to work fully under passive feeding conditions (Fig. 1b). In addition, three supercapacitors have been implemented, that are recharged by the fuel cell, for eventual larger power demands up to 40 W. Hydrogen is stored in two metal hydride canisters with 2g capacity to provide 30 W h energy enough for a few hours autonomy. In addition, for fuel cell parameters monitoring, different sensors have been implemented that provide voltages of the individual cells, current, and temperatures. The sensors are connected to Arduino board, and measurements are continuously monitored by a Labview software with wifi. Boost dc-dc conversion provides 7V voltage power to feed the motors. The stack prototype allows for different testing configurations, using cells in series and parallel connection to change power characteristics with different voltage and current. Results of the testing are provided in this communication. Acknowledgement: The work is partially financed by the ELHYPORT project (PID2019−110896RB-I00), Spanish Ministry of Science and Innovation. Figure 1
Thanaphorn Hakhen
· 2014
This research presents the application of model predictive control (MPC) to control a proton exchange membrane fuel cell (PEMFC). Firstly, the steady state analysis of PEMFC is considered to select its suitable operating conditions based on cell electrical characteristics. Then, the effect of input parameters on cell voltage and temperature is analyzed to investigate the dynamic behavior of PEMFC that is important for control design. It is found that the cell voltage and cell temperature depend on the inlet molar flow rates and temperature of hydrogen and air, and operating current density. To obtain an efficient control system, the control structure design of the PEMFC is considered to specify a good choice of the controlled and manipulated variables. An analysis of the steady-state relative gain array (RGA) is used for pairing of the controlled and manipulated variables. The result shows that the inlet molar flow rates of hydrogen and air are manipulated variables to regulate the cell temperature and partial pressure of hydrogen, respectively. Finally, a model predictive control (MPC) is developed and designed for controlling the cell temperature and partial pressure of hydrogen. Basically, MPC requires the process model used in its control algorithm. The PEMFC model is known to be complicated and involves uncertain parameters. Thus, an offline robust model predictive control (robust MPC) based on a linear time-varying (LTV) model is proposed for PEMFC control. The simulation results show that the robust MPC shows better control performance than conventional MPC because the robust MPC can guarantee robust stability.
H.‐P. Schmid, J. A. Wünning
Fuel Cells · 2004
Abstract Primary energy savings and CO 2 reduction is one of the key motivations for the use of fuel cell systems in the energy sector. A benchmark of domestic cogeneration by PEMFC with existing large scale power production systems such as combined steam‐gas turbine cycle, clearly reveals that only fuel cell systems optimising overall energy efficiency (> 85%) and electrical efficiencies (> 35%) show significant primary energy savings, about 10%, compared with the best competing technology. In this context, fuel processing technology plays a dominant role. A comparison of autothermal and steam reforming concepts in a PEMFC system shows inherent advantages in terms of efficiency at low complexity for the latter. The main reason for this is that steam reforming allows for the straightforward and effective use of the anode‐off gas energy in the reformer burner. Consequently, practical electrical system efficiencies over 40% seem to be achievable, most likely by steam reformers. FLOX®‐steam reforming technology has reached a high state of maturity, offering diverse advantages including: compact design, stable anode off‐gas usage, high efficiency, as well as simple control behaviour. Scaling of the concept is straightforward and offers an opportunity for efficient adaptation to smaller (1 kW) and larger (50 kW) units.
P Rama, R Chen, R Thring
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy · 2005
A mathematical multi-species modelling framework for polymer electrolyte fuel cells (PEFCs) is presented on the basis of fundamental molecular theory. Characteristically, the resulting general transport equation describes transport in concentrated solutions and also explicitly accommodates for multi-species electro-osmotic drag. The multi-species nature of the general transport equation allows for cross-interactions to be considered, rather than relying upon the superimposition of Fick's law to account for the transport of any secondary species in the membrane region such as hydrogen. The presented general transport equation is also used to derive the key transport equations used by the historically prominent PEFC models. Thus, this work bridges the gap that exists between the different modelling philosophies for membrane transport in the literature. The general transport equation is then used in the electrode and membrane regions of the PEFC with available membrane properties from the literature to compare simulated one-dimensional water content curves, which are compared with published data under isobaric and isothermal operating conditions. Previous work is used to determine the composition of the humidified air and fuel supply streams in the gas channels. Finally, the general transport equation is used to simulate the crossover of hydrogen across the membrane for different membrane thicknesses and current densities. The results show that at 353 K, 1 atm, and 1 A/cm 2 , the nominal membrane thickness for less than 5 mA/cm 2 equivalent crossover current density is 30 μm. At 3 atm and 353 K, the nominal membrane thickness for the same equivalent crossover current density is about 150 μm and increases further to 175 μm at 383 K with the same pressure. Thin membranes exhibit consistently higher crossover at all practical current densities compared with thicker membranes. At least a 50 per cent decrease in crossover is chieved at all practical current densities, when the membrane thickness is doubled from 50 to 100 μm.
M. Muthukumar, P. Karthikeyan, V. Lakshminarayanan et al.
Applied Mechanics and Materials · 2014
The geometrical and flow parameters are governing the performance of the Proton Exchange Membrane Fuel Cell (PEMFC). The flow channels are used for distributing the reactants uniformly throughout the active area of fuel cell. Among different flow field designs, the serpentine flow field can give better performance to the PEM fuel cell. This paper numerically investigates the effects of the serpentine flow field with different number of passes. The 2 pass, 3 pass and 4 pass serpentine flow field designs of same rib size and channel size were modelled and analyzed using commercially available software package. From the polarization curves and performance curves drawn using the numerical results, the performance of three flow channel designs were compared and the maximum power densities of each design were found
Guruviah Velayutham, Srinivas Sribollepalli, P Kalingamuthu
ECS Meeting Abstracts · 2014
Gas diffusion layer (GDL) plays a very important role in the function of fuel cell performance. Therefore, the requirements of an ideal GDL include diffusion and distribution of reactants to the catalyst layers, good in plane and thro plane conductivity. Depending on the reactants and operating current densities, the GDL must provide an optimum hydrophobicity and hydrophilicity for gas distribution, water and thermal management (1-3). In order to improve the stability of fuel cell stack, a complete understanding of GDL properties are essential. In the present work, AvCarb MGL370 carbon paper and AvCarb 1071 carbon cloth is used as a substrate material. The effect of PTFE content on the substrate and micro-porous layer on the fuel cell performance is compared in both hydrogen/oxygen and hydrogen/air. The properties of GDL were characterized by experimental setup developed in house for the measurement of gas diffusion coefficient. The properties were also measured using Capillary Flow Porosity meter. The percentage of PTFE on the substrate is varied for both carbon paper as well as carbon cloth ranging from 5 to 20%, however the concentration of PTFE in the micro layer is fixed. The experiments are conducted by keeping constant PTFE loading in the substrate while the concentration PTFE in the micro layer is varied from 15 to 30%. The PEMFC cells were tested at 65 o C and at ambient pressure with relative humidity of hydrogen and air kept at 90% and 80%, respectively. The results were analyzed from the polarization curves. The long-term stability of the cell is evaluated by operating the cell at constant current density. PTFE content in the substrate as well as micro porous layer is important for the performance of fuel cell. The current density achieved in the hydrogen/oxygen is about 1.25A/cm2 at 0.6V, while the same electrode when operated with hydrogen air is 0.5A/cm2 at the same operating voltage (GDL1). Alteration of both substrate and micro-layer PTFE concentration improve the performance to 1.6A/cm2 and 0.7A/cm2 at 0.6V for hydrogen/oxygen and hydrogen/air respectively (GDL2),Fig.1. The effect of hot pressing condition on both carbon cloth as well as carbon paper is also discussed. The pressing pressure conditions varied from 40 to 120kg/cm2. In this paper the performance of both carbon paper and carbon cloth is discussed with respect to PTFE content and pressing conditions. Fig.1: The effect of PTFE content in the substrate and micro layer, ambient pressure, temperature of operation 65 o C, H 2 /O 2 - 100/80%, flow rate H 2 /O 2 is 300/400cc References: 1. G. Velayutham, J. Kaushik , N.Rajalakshmi , K.S.Dhathathreyan , Fuel Cell 7, 314-318 (2007) 2. G. Velayutham, International Journal of Hydrogen Energy 36(22), 14845-14850, (2011) 3. E.Passalacqua , G.Squadrito, F.Lufrano , A.Patti, L.Giorgi . J Appl Electrochem , 31, 449-54 ( 2001)
Yunqi Li, Danping Xiong, Yuwei Liu et al.
Nanotechnology Reviews · 2019
Abstract The catalysts performance degradation is a crucial issue in decay of the polymer electrolyte membrane fuel cell (PEMFC). The effect of Nafion content, dispersity of Pt nanoparticles and selected types of carbon support on the degradation of electrochemical surface area (ECSA) and double layer capacitance (DLC) were experimentally discussed by accelerated stress test (AST). The catalyst with 20wt% Nafion content exhibited better catalyst performance. i.e ., the less DLC and ECSA degradation during AST. Catalysts with well Pt dispersity showed superior %ECSA (the percentage change of ECSA) retention. The heat-treated catalysts exhibited the lowest ECSA and DLC degradation rate due to the larger Pt particle and high carbon corrosion resistance. Moreover, a multi-order model describing the correlation between ECSA and DLC degradation was proposed, providing a vital reference for quantitatively investigating ECSA and DLC degradation in the catalysts with different catalysts structural parameters.
Hegazy Rezk, Ahmed Fathy
Sustainability · 2020
The output power of a fuel cell mainly depends on the operating conditions such as cell temperature and membrane water content. The fuel cell (FC) power versus FC current graph has a unique maximum power point (MPP). The location of the MPP is variable, depending on the operating condition. Consequently, a maximum power point tracker (MPPT) is highly required to ensure that the fuel cell operates at an MPP to increase its performance. In this research work, a variable step-size incremental resistance (VSS-INR) tracking method was suggested to track the MPP of the proton exchange membrane (PEMFC). Most of MPPT methods used with PEMFC require at least three sensors: temperature sensor, water content sensor, and voltage sensor. However, the proposed VSS-INR needs only two sensors: voltage and current sensors. The step size of the VSS-INR is directly proportional to the error signal. Therefore, the step size will become small as the error becomes very small nearby the maximum power point. Accordingly, the accuracy of the VSS-INR tracking method is high in a steady state. To test and validate the VSS-INR, nine different scenarios of operating conditions, including normal operation, only temperature variation, only variation of water content in the membrane, and both variations of temperature and water content simultaneously, were used. The obtained results were compared with previously proposed methods, including particle swarm optimization (PSO), perturb and observe (P&O), and sliding mode (SM), under different operating conditions. The results of the comparison confirmed the superiority of VSS-INR compared with other methods in terms of the tracking efficiency and steady-state fluctuations.
Yang Zhao, Xue Li, Shubo Wang et al.
ECS Meeting Abstracts · 2019
Direct membrane deposition is introduced as a novel polymer electrolyte membrane fabrication method. This method is extended to fabricate a high-performance membrane electrode assembly for polymer electrolyte membrane fuel cell with poly (arylene ether sulfone) nanofibers as effective membrane reinforcements. The nanofibers are directly electrospun onto gas diffusion electrodes. By spray-coating ionomer dispersion into the pore space of nanofiber mats, composite membranes of 15 μm thickness are fabricated. The introduction of the electrically and ionically insulating nanofibers do not hamper the cell performance. At 80 ℃ and 75% relative humidity, the power density of the fuel cell employing direct membrane deposition, 2.85 W/cm 2 , is about 1.36 times higher than that of the reference fuel cell (2.09 W/cm 2 ) with Nafion ® 211. Its cell resistance (28 mΩ·cm 2 ) is much lower than that of the membrane electrode assembly fabricated by the catalyst coating membrane method (46 mΩ·cm 2 ). The performance differences between two fabrication methods are systematically analyzed by electrochemical impedance spectroscopy. Even though the thickness of the polymer electrolyte (15 μm) is much lower than that of Nafion ® 211, it shows much higher internal short resistance because of the existence of nanofibers.
Dinesh Kumar Madheswaran
Green and Low-Carbon Economy · 2023
This article explores the potential and limitations of Sediment Microbial Fuel Cells (SMFCs) and their deployment for sustainable energy production and environmental remediation. SMFCs use naturally occurring redox gradients in sediments to produce bioelectricity, making them advantageous over conventional energy sources due to their affordability, simplicity, and ability to operate in various environments with minimum maintenance requirements. However, their low power output density restricts their practical applicability. The article discusses the controllable and uncontrollable factors that affect SMFC performance and their influence on SMFC functionality, electrode material, external resistance, electrode spacing, electrode design, electrode immersion dimensions, and catalyst. The article highlights the challenges facing SMFC deployment, particularly in large-scale businesses, such as the need for more scientific literature on SMFCs and inadequate focus on energy metrics.
Richard T. Meyer, Bin Yao
ASME 2006 Fourth International Conference on Fuel Cell Science, Engineering and Technology, Parts A and B · 2005
Recent trends and advances in hydrogen/air Proton Exchange Membrane Fuel Cells (PEMFC) are incorporated into a dynamic control oriented model. This type of model is important for development of control systems for PEMFC powered transportation where unpredictable and widely varying changes in power demand can be expected. Self humidification and low pressure operation are the two major changes to past systems. As a result, a high pressure air compressor, air cooler, and inlet gas humidifiers are no longer required. Also, the likelihood of cathode flooding is reduced. The overall fuel cell model consists of four basic sub-models: anode, cathode, fuel cell body, and cooling. Additionally, the oxidant supply blower, cooling pump, and cooling fan are explicitly incorporated. Mass and energy conservation are applied to each using a lumped parameter control volume approach. Empirical modeling is minimized as much as possible, however it is necessary for model manageability in a control context. Interactions between each subsystem and balance of plant components are clearly defined. The overall model is capable of capturing the transient behavior of the flows, pressures, and temperatures as well as net output power. The influence of the charge double layer effect on transient performance is also explored. Numerical simulations of the system are presented which illustrate the usefulness of the model. Finally, future control work is described.
Borker Mohnish, Suchithra T.V
International Journal of Engineering & Technology · 2018
The need for a sustainable source of energy has catered engineers to discover and develop a biological battery known as Plant Microbial fuel cell. This biological battery operates with the help of electrochemically active bacteria in presence of CO2, sunlight and water. This technique is gaining importance in the field of bioelectricity as it produces clean in-situ energy from living plants without the need to harvest the plant species. Research on these cells have led to the development of various models. One such plant species Setaria faberi was tested for its compatibility in sediment plant microbial fuel cell. Power density of 4.6mW/m2 was obtained when it was tested with cocopeat as a hydroponic media. This paper highlights the suitability of S. faberi in producing sustainable bioelectricity with a hydroponic media. Â
Sameer Al-Asheh, Yousef Al-Assaf, Ahmed Aidan
Energies · 2020
A Microbial Fuel Cell (MFC) is a process in which a microorganism respires and captures the electrons that normally passes through the electron transport system of the organism and produces electricity. This work intends to present the different operating parameters affecting the efficiency of a Microbial Fuel Cell (MFC) process. To study the performance of the process, various materials for the cathode and anode rods with similar size and chape including, copper, aluminum, carbon cloth, steel and brass were considered to determine the combination that leads to the best results. Moreover, different oxidizing agents such as Copper Sulphate and Potassium Hexacyanoferrate were considered. Furthermore, the effects of shapes, sizes and distance between electrodes on the current and voltage were investigated. The power outputs between electrochemical and microbial cells were recorded. In addition, the power, whether expressed as voltage or current, was measured at different conditions and different cell combinations. The power is directly related to the area, volume of the bacterial solution and supplying air and stirring.
M. Aliasghary
Fuel Cells · 2018
Abstract In this study, an interval type‐2 fuzzy proportional–integral–derivative (IT2FPID) controller is designed to be used in the air flow regulation of polymer electrolyte membrane fuel cell (PEMFC) systems. The proposed controller is able to handle the effect of external disturbances and fix the oxygen excess ratio at an appropriate set‐point. Three crisp singletons for the output and two interval type‐2 membership functions for the inputs are defined for the suggested controller. Two conventional controllers including type‐1 fuzzy PID (T1FPID) and ordinary proportional–integral–derivative (PID) are also investigated to evaluate the performance and efficiency of this technique. The results of various simulations indicate that the IT2FPID controller has a better performance and transient response compared to the other approaches.
Calvin H. Li, G. P. Peterson
Advances in Mechanical Engineering · 2009
A combined experimental and analytical investigation of single proton exchange membrane (PEM) fuel cells, during cold start, has been conducted. The temperature influence on the performance of a single PEM fuel cell and the cold start failure of the PEM fuel cell was evaluated experimentally to determine the failure mechanisms and performance. The voltage, current, and power characteristics were investigated as a function of the load, the hydrogen fuel flow rate, and the cell temperature. The characteristics of cold start for a single PEM fuel cell were analyzed, and the various failure mechanisms were explored and characterized. In an effort to better understand the operational behavior and failure modes, a numerical simulation was also developed. The results of this analysis were then compared with the previously obtained experimental results and confirmed the accuracy of the failure mechanisms identified.
Yong Yuan, Qing Chen, Shungui Zhou et al.
Journal of Chemical Technology & Biotechnology · 2011
Abstract BACKGROUND: Electricity can be generated directly from sewage sludge with a microbial fuel cell (MFC), combining degradation of organic matter. This study constructed a novel insert‐type air‐cathode microbial fuel cell (ITAC‐MFC) as an alternative to a sediment‐type MFC and a two‐chambered MFC for the generation of bioelectricity and the degradation of sewage sludge organic matter. Meanwhile, a pH adjustment was carried out to enhance substrate bioavailability of sludge and to suppress methane production in the MFC. RESULTS: A maximum power density of 73 ± 5 mW m −2 was obtained at sludge pH 10.0, much higher than those of 33 ± 3 and 4 ± 0.5 mW m −2 obtained at pH 8.0 and 6.0, respectively. It was observed that the soluble chemical oxygen demand (SCOD) of sewage sludge at pH 10.0 was almost three times greater than that at pH 6.0. At the same time, the total chemical oxygen demand (TCOD) removal and coulombic efficiency (CE) at pH 10.0 were also much higher than at the other two conditions. CONCLUSIONS: The results demonstrated that improved electricity production and organic degradation could be achieved by maintaining the sludge pH at 10.0 in an MFC. ITAC‐MFC offers an attractive alternative for the environmentally‐friendly removal of organic matter in sewage sludge. Copyright © 2011 Society of Chemical Industry
Hugo Guillermo Jimenez Pacheco, Abdel Alejandro Portocarrero Banda, Eric Ivan Vilca Cayllahua et al.
Energies · 2023
The generation of energy through the transformation of polluting waste is a widely explored field and offers advances in green technologies. One of the promising technologies is Microbial Fuel Cells (MFCs). These cells can contain electroactive microorganisms that transform organic waste into electricity by transferring electrons from their metabolism. In this study, a new bacterium capable of producing electricity from the waste of the poultry sector and using copper electrodes, called Av_G1, was identified and isolated. It is phylogenetically related to Citrobacter freundii and Citrobacter Murlinae. This new strain was identified molecularly, biochemically, and phylogenetically; its physiological and morphological characteristics were also studied through a Scanning Electron Microscope (SEM). Biochemical determination was performed using Simmons Citrate Agar, Lysine Iron Medium (L.I.A.), Motility/Ornithine Test, Methyl Red indicator, Enzymes: oxidase and catalase, and Gram stain test. The phylogenetic inference was deduced by bioinformatics tools (MEGA X, JalView, Clustal Omega) and the genetic databases The Ribosomal Database Project—RDP and the National Center for Biotechnology Information (NCBI). A maximum current potential of 0.645 V, a maximum current density of 168.72 ± 14.07 mA/m2, and a power density of 31.05 mW/m2 were recorded. During the monitoring, the physicochemical parameters were taken: pH, Oxide Reduction Potential (ORP), Dissolved Oxygen (DO), conductivity, Total Solids (TDS), and average temperature were recorded. Therefore, the present study shows a new Gram-negative electrogenic bacterium, which can be used for electrochemical processes and applied in MFC with copper electrodes.
Guanghua Wei, Jiabin Lu, Fengjuan Zhu et al.
ECS Meeting Abstracts · 2016
The polymer electrolyte membrane fuel cell (PEMFC) possesses many advantages for both automotive and stationary application, including high energy efficiency, low operating temperature, zero emission, and so on. Aside from the fact that great improvement should be made on its key materials, i.e., the ORR electrocatalysts and proton exchange membrane, it is believed that the PEM fuel cell performance is greatly affected by the operating temperature, gas inlet humidity as well as the flow pattern, and so on [1,2]. Thus, in this work, a 3D steady state model is established to investigate detailedly the effects of the flow pattern (co-flow and counter-flow), the anode and cathode gas inlet relative humidity (RH) on the cell performance. The governing equations of the 3D model result from careful analysis on the electro-chemical reactions, current conservation, membrane proton migration, membrane water transport and water-vapor phase transition. The membrane water transport takes into accounts the electro-osmatic drag and water back diffusion, and the conservation of momentum, species and energy is applied to all components of the PEM fuel cell. Experimental validation is also performed and fits very well with the simulation. Figure 1 shows the current density distribution for different flow patterns: (a), co-flow and (b), counter-flow. The corresponding achievement will offer an efficient guide on the design and performance optimization of PEMFC. Acknowledgements This work was supported in part by National Natural Science Foundation of China (Grant No. 21373135 and 21533005) and Science Foundation of Ministry of Education of China ( Grant No. 413064). References K. Dannenberg, P. Ekdunge, G. Lindbergh, Mathematical model of the PEMFC, Journal of Applied Electrochemistry, 2000, 30: 1377-1387. S.H. Ge, B.L. Yi, A mathematical model for PEMFC in different flow modes, Journal of power sources, 2003, 124: 1-11. Figure 1
Farzaneh Rezaei, Defeng Xing, Rachel Wagner et al.
Applied and Environmental Microbiology · 2009
ABSTRACT Electricity can be directly generated by bacteria in microbial fuel cells (MFCs) from many different biodegradable substrates. When cellulose is used as the substrate, electricity generation requires a microbial community with both cellulolytic and exoelectrogenic activities. Cellulose degradation with electricity production by a pure culture has not been previously demonstrated without addition of an exogenous mediator. Using a specially designed U-tube MFC, we enriched a consortium of exoelectrogenic bacteria capable of using cellulose as the sole electron donor. After 19 dilution-to-extinction serial transfers of the consortium, 16S rRNA gene-based community analysis using denaturing gradient gel electrophoresis and band sequencing revealed that the dominant bacterium was Enterobacter cloacae . An isolate designated E. cloacae FR from the enrichment was found to be 100% identical to E. cloacae ATCC 13047 T based on a partial 16S rRNA sequence. In polarization tests using the U-tube MFC and cellulose as a substrate, strain FR produced 4.9 ± 0.01 mW/m 2 , compared to 5.4 ± 0.3 mW/m 2 for strain ATCC 13047 T . These results demonstrate for the first time that it is possible to generate electricity from cellulose using a single bacterial strain without exogenous mediators.
Yi-Ta Wang, Chyow-San Chiou, Shao-Yu Chang et al.
Journal of Nanoscience and Nanotechnology · 2020
This study focused on an iron phthalocyanine compound with aligned CNTs on the surface of a carbon felt electrode (FePc/CNT/C) to enhance the bio-electro-Fenton microbial fuel cell system cathodes reaction rate of hydrogen peroxide and the electrical plate. Experiments of polarization curves and power density, decolorization of Reactive Black 5 (RB5), and scanning electron microscopy (SEM) measured the characteristics of the cathode plate. FePc/CNT/C presented better electrical properties (open-circuit voltage, maximum current density, and maximum power density) than that of CNT/C and C, as FePc is a catalyst and its planar structure could easily adhere to CNT to enhance the reduction reaction at the cathode and provide higher specific surface area. The optimal decolorization of RB5 dye, as achieved with the FePc/CNT/C electrode, was 61.79% among the three cathode electrodes in the bio-electro-Fenton microbial fuel cell system, and the maximum number of hydroxyl radicals was generated for the cathode electrode of FePc/CNT/C. These results suggest that the bio-electro-Fenton microbial fuel cell system could be applied as an energy-saving and efficient approach for dye-containing wastewater treatment.
Alwahab Alwahab, Pratitis Tri Maharani, Wa Ode Miranda Nur K. et al.
Advance Sustainable Science, Engineering and Technology · 2024
This study examines the potential of biogas liquid waste as a source of electrical energy through microbial fuel cell (MFC) technology. The results showed that biogas effluent in one-room MFC produced a maximum voltage of 1302.2 mV. In the two-room MFC with KMnO4 electrolyte, the voltage reached 1084.3 mV with an electric current of 0.1 mA. At the same time, the two-chamber MFC with K2Cr2O4 advanced a maximum voltage of 1675.8 mV and an electric current of 0.99 mA. Characterization of the MFC substrate showed a decrease in organic matter of biogas liquid waste, with C-organic content of 2.20%, total nitrogen of 1.85%, and C/N ratio of 1.19. The COD value decreased to 500.96 mg/L, while the BOD level decreased to 300.23 mg/L. Bacteria in MFC from biogas effluent are dominantly Gram-positive with rod and Sarcina forms, except for one Gram-negative isolate in the form of Spirillum.
Viatcheslav Fedorovich, Matthew C. Knighton, Eulyn Pagaling et al.
Applied and Environmental Microbiology · 2009
ABSTRACT Exoelectrogenic bacteria are organisms that can transfer electrons to extracellular insoluble electron acceptors and have the potential to be used in devices such as microbial fuel cells (MFCs). Currently, exoelectrogens have been identified in the Alpha -, Beta -, Gamma - and Deltaproteobacteria , as well as in the Firmicutes and Acidobacteria . Here, we describe use of culture-independent methods to identify two members of the genus Arcobacter in the Epsilon p roteobacteria that are selectively enriched in an acetate-fed MFC. One of these organisms, Arcobacter butzleri strain ED-1, associates with the electrode and rapidly generates a strong electronegative potential as a pure culture when it is supplied with acetate. A mixed-community MFC in which ∼90% of the population is comprised of the two Arcobacter species generates a maximal power density of 296 mW/liter. This demonstration of exoelectrogenesis by strain ED-1 is the first time that this property has been shown for members of this genus.
Changman Kim, Young Eun Song, Cho Rong Lee et al.
Journal of Industrial Microbiology and Biotechnology · 2016
Abstract Glycerol is an attractive feedstock for bioenergy and bioconversion processes but its use in microbial fuel cells (MFCs) for electrical energy recovery has not been investigated extensively. This study compared the glycerol uptake and electricity generation of a co-culture of Shewanella oneidensis MR-1 and Klebsiella pneumonia J2B in a MFC with that of a single species inoculated counterpart. Glycerol was metabolized successfully in the co-culture MFC (MFC-J&M) with simultaneous electricity production but it was not utilized in the MR-1 only MFC (MFC-M). A current density of 10 mA/m2 was obtained while acidic byproducts (lactate and acetate) were consumed in the co-culture MFC, whereas they are accumulated in the J2B-only MFC (MFC-J). MR-1 was distributed mainly on the electrode in MFC-J&M, whereas most of the J2B was observed in the suspension in the MFC-J reactor, indicating that the co-culture of both strains provides an ecological driving force for glycerol utilization using the electrode as an electron acceptor. This suggests that a co-culture MFC can be applied to electrical energy recovery from glycerol, which was previously known as a refractory substrate in a bioelectrochemical system.
Zarar Ahmed, Tehmoor Ellahi, Alin Ciobica et al.
International Journal of Energy Research · 2024
Energy crisis and wastewater treatment are critical global issues. In this study, a novel separator was made by boiling cotton rope with solutions of various salts and their concentrations. It was then employed in a dual‐chamber microbial fuel cell (MFC) to treat municipal wastewater collected from 25 Area Wah Cantt, Punjab, Pakistan. Batch scale experiments were carried out to evaluate the effect of various variables, that is, different salts (NaCl, KCl, and MgCl 2 ) and their concentrations (0.2, 0.5, and 1 M) used in separator, wastewater volume (50, 500, and 1000 mL), and aluminum mesh thickness (0.6, 0.8, and 1 mm) on MFC performance in terms of current generation and wastewater treatment for 7 days. Analysis of collected wastewater showed that among the six studied physicochemical parameters, only two, that is, biological oxygen demand (BOD) and chemical oxygen demand (COD) were above the permissible limits of National Environmental Quality Standards (NEQS). Results after MFC experiments showed that separator containing 0.5 M NaCl produced a significantly ( p < 0.05) high current of 68.16 µA as compared to the other studied salts and their concentrations, whereas COD and BOD were reduced up to 124.15 and 62.12 mg L −1 , respectively. A wastewater volume of 1000 mL generated a significantly ( p < 0.05) high current of 83.41 µA compared to the other studied volumes, where COD and BOD residual values were 123.25 and 59.56 mg L −1 , respectively. An aluminum mesh thickness of 1 mm produced a significantly ( p < 0.05) high current of 103 µA, while 120.89 and 68.93 mg L −1 were achieved COD and BOD values, respectively. It was concluded that MFC performance was enhanced with an increase in wastewater volume and mesh thickness. Therefore, it is recommended that further pilot‐scale continuous studies be carried out to implement this research on a larger scale.
Mbugua J K, Kinyua A, Mbui D N et al.
American Journal of Environment and Climate · 2022
In microbial fuel cell technology, the substrate is consumed by microbes in anaerobic conversion of substrate to electricity. Bio-remediation of pollutants involves microbial environmental cleanup using green approach. The primary problems with pesticides are linked to the non-negligible proportion of the sprayed active ingredient that does not reach its intended target thereby contaminating environmental compartments persistently. The primary objective of this study was to assess the potential of microbial fuel cell technology in bio-remediation of lambda cyahlothrin, chlorpyrifos and malathion in Limuru loam soil. H-shaped double chamber microbial fuel cell was fabricated where the anodic chamber was loaded with 750 mL loam soil inoculated with 750 mL bio-slurry doped with 10 mL of 10 ppm lambda cyhalothrin, chlorpyrifos and malathion pesticide solutions. The cathodic chamber was loaded with 1500 mL distilled water. The setup was incubated for a 90 days retention time where voltage and current were recorded daily using a multi-meter. The degradation level was assessed using a GC-MS after sample extraction using standard QuEChERs method. The voltage generated from the pesticide doped loam soil showed an upward trend from day 0 to day 15 in lambda cyhalothrin and malathion and from day 0 to day 20 in chlorpyrifos and pesticide mixture after which constant readings were observed for three days with downward trends thereafter. The maximum generated voltage was 0.537 V, 0.571 V, 0.572 V and 0.509 V in chlorpyrifos, lambda cyhalothrin, malathion and pesticide mix (MCL) respectively. The bioremediation levels for chlorpyrifos and malathion were 65.80 % and 71.32 %, respectively while no detectable, lambda cyhalothrin was observed after day 60 of the study. This study concludes that bioremediation of lambda cyhalothrin, chlorpyrifos and malathion in Limuru loam soil can be achieved using microbial fuel cells.
M. Z. M. Muaz, R. Abdul, V. M. Vadivelu
Environmental Progress & Sustainable Energy · 2018
Microbial fuel cells (MFC) haves drawn much attention as a potential approach for sludge treatment and renewable energy production. In this study, a single chamber air‐cathode in a membrane‐less MFC (ML‐MFC) was operated in batch mode with dewatered sludge from a municipal wastewater treatment plant as the substrate. Electrogenic bacterial species in the sludge acted as a catalyst for the generation of electricity. The performance of the ML‐MFC was evaluated using one‐factor‐at‐a‐time (OFAT) method followed by response surface methodology (RSM) via Central Composite Design using a quadratic model. In the preliminary OFAT study, the highest voltage generation (852.7 mV) and COD removal (149.2 mg/L) were obtained when the pH, electrode distance, moisture content, and temperature were at 6.0, 3 cm, 30% (vol/wt), and 35°C, respectively. After incubation of the ML‐MFC using optimum conditions suggested by the RSM, the voltage was successfully increased to 927.7 mV (improved 9%), while COD removal increased to 170.8 mg/L (improved 15%). This showed that optimization using RSM gave better results than the OFAT method. The maximum power density recorded from the optimum conditions was 41.3 mW/m 2 . © 2018 American Institute of Chemical Engineers Environ Prog, 38: 208–219, 2019
Khaya Pearlman Shabangu, Manimagalay Chetty, Babatunde Femi Bakare
Energies · 2024
Microbial fuel cells (MFCs) have garnered significant attention due to their capacity to generate electricity using renewable and carbon-neutral energy sources such as wastewater. Extensive experimental work and modeling techniques have been employed to dissect these processes and understand their respective impacts on electricity generation. The driving force is to enhance MFC performance for practical applications commercially. Among the various statistical modeling approaches, one particularly robust tool is the Design of Experiments (DoE). It serves to establish the relationships between different variables that influence MFC performance and allows for the optimization of the MFC configuration and operation for scaled-up performances in terms of bioelectricity generation. This study focused on optimizing microbial fuel cells (MFCs) for bioelectricity production using industrial wastewater treatment, employing the Box–Behnken design (BBD) methodology. Through an analysis of response surface models and ANOVA tests, it was found that a combined approach of reduced quadratic, reduced two-factor interaction, and linear models yielded sound results, particularly in voltage yield, COD removal, and current density. Second-order regression models predicted optimal conditions for various parameters, with surface area, temperature, and catholyte dosage identified as critical input variables for optimization. Under these conditions, conducted by the four-factor and three-level Box–Behnken design methodology in a double-chamber MFC unit considering eight output variables—CCV yield, % COD removal, current density, power density, % TSS removal, % CE, and % PO43−—the optimum values were 700 mV, 54.4%, 54.4 mA/m2, 73.7 mW/m2, 99%, 21.2%, and 100%, respectively. At optimum operating conditions, the results revealed a desirability of 76.6% out of a total of 92 iterations. The paper highlights the effectiveness of statistical ANOVA fit-statistics modeling and optimization in enhancing DCMFC performance, recommending its use as a sustainable bioenergy source. Furthermore, validation results supported the above optimization output response findings and confirmed the viability of biorefinery wastewater as an anolyte for scaling up DCMFC bioelectricity generation.
A A Fedotov, A B Tarasenko, D A Karanova
Journal of Physics: Conference Series · 2020
Abstract The gas diffusion layer (GDL) plays an important role in the operation of fuel cells with a proton exchange membrane (PEMFC). GDL is commonly used on three possible types of carbon fiber-con backing: carbon fabric, non-woven material, carbon paper. All three types have different properties, such as gas permeability, mechanical strength, electrical resistance, hydrophilicity and price. Paper is much cheaper than non-woven material, and replacing even one electrode could make a fuel cell cheaper. But replacement makes sense only if the same efficiency is maintained. In this work, two types of GDL as an anode in PEMFC were compared. As a result of the comparison, current-voltage and power characteristics were obtained.
E. Pichot, M. Olivon, A. Perraud et al.
Fuel Cells · 2020
Abstract A Ni/Yttria‐stabilized zirconia (YSZ) cell with a (La 0.60 Sr 0.40 ) 0.95 Co 0.20 Fe 0.80 O 3– δ cathode is tested both in fuel cell and electrolysis modes. In fuel cell mode under dry air and wet H 2 , the cell is operated between the open circuit voltage (OCV) and 0.4 V and reaches 330 mW cm −2 at 850 °C for 157 mL min −1 H 2 supply. The influence of temperature and air or hydrogen flow rate is studied, and impedance measurements show that below 0.8 V the electrolyte becomes the more resistive part of the cell. Nevertheless, fuel utilization yields are higher under oxygen or hydrogen depletion. If it is possible at 750 °C to work at low voltage during several hours in the entire voltage range, the voltage decrease must be limited at 850 °C. The cell can also be operated under wet air. The same cell can be operated in electrolysis mode, and a power density of 340 mW cm −2 can be obtained at 0.3 V/OCV under 100 mL min −1 wet (3% H 2 O) 5% H 2 –95% Ar mixture on the fuel side and dry or wet 100 mL min −1 air flow on the air side. Nevertheless, bubbling air providing the air electrode in saltwater has an irreversible detrimental effect on the cell.
Kiran K. Jayaraj, Prakash Saravanan, Gourav Dhar Bhowmick
Energies · 2023
The sustainable development of aquaculture faces a significant challenge due to the need for the frequent treatment of aquacultural waste. This research presents a pioneering solution by concurrently utilizing aquacultural waste to produce biochar and enhancing a sediment microbial fuel cell (SMFC)’s treatment efficacy for waste generated from the integrated multitrophic aquaculture (IMTA) system. The water quality parameters of the aquacultural pond water were analyzed, and synthetic wastewater was prepared to validate the system’s efficiency. Over a period of more than 50 days, the SMFC was operated and monitored, yielding an average chemical oxygen demand (COD) removal efficiency of 86.31 ± 2.18%. The maximum operating voltage of the SMFC reached 0.422 V on the 21st day of operation when connected to an external resistance of 975 Ω. A novel-activated aquacultural biochar catalyst was synthesized from aquaponics waste and used as a cathode catalyst, substantially improving the SMFC’s performance. Characterization studies demonstrated that the aquacultural biochar catalyst was an active electrocatalyst, accelerating the oxygen reduction reaction rate and leading to increased power output and overall efficiency of the SMFC. The SMFC utilizing the aquacultural-waste-based biochar cathode catalyst showcased the highest maximum power density, with a range of 101.63 mW/m2 (1693.83 mW/m3), and the lowest internal resistance, indicating superior performance. These results validate the reliability of implementing SMFCs in actual aquaculture systems. A novel modular design for SMFC reactor-assisted small-scale integrated poultry–fish culture systems is proposed for further practical application in real-life aquaculture settings. This research contributes to finding sustainable and effective methods for waste treatment for aquaculture, promoting the development of environmentally friendly practices in the industry.
Enas Taha Sayed, Hussain Alawadhi, Khaled Elsaid et al.
Sustainability · 2020
Microbial fuel cell (MFC) is an emerging method for extracting energy from wastewater. The power generated from such systems is low due to the sluggish electron transfer from the inside of the biocatalyst to the anode surface. One strategy for enhancing the electron transfer rate is anode modification. In this study, iron nanostructure was synthesized on a carbon cloth (CC) via a simple electroplating technique, and later investigated as a bio-anode in an MFC operated with real wastewater. The performance of an MFC with a nano-layer of iron was compared to that using bare CC. The results demonstrated that the open-circuit voltage increased from 600 mV in the case of bare CC to 800 mV in the case of the iron modified CC, showing a 33% increase in OCV. This increase in OCV can be credited to the decrease in the anode potential from 0.16 V vs. Ag/AgCl in the case of bare CC, to −0.01 V vs. Ag/AgCl in the case of the modified CC. The power output in the case of the modified electrode was 80 mW/m2—two times that of the MFC using the bare CC. Furthermore, the steady-state current in the case of the iron modified carbon cloth was two times that of the bare CC electrode. The improved performance was correlated to the enhanced electron transfer between the microorganisms and the iron-plated surface, along with the increase of the anode surface- as confirmed from the electrochemical impedance spectroscopy and the surface morphology, respectively.
Tianyi Yang, Song Xue, Liming Jiang et al.
Coatings · 2025
Microbial fuel cells (MFCs) generate electricity through the microbial oxidation of organic waste. However, the inherent electrochemical performance of carbon felt (CF) electrodes is relatively poor and requires enhancement. In this study, nickel oxide (NiO) was successfully loaded onto CF to improve its electrode performance, thereby enhancing the electricity generation capacity of MFCs during the degradation of treated wastewater. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy diffusion spectrometer (EDS) analyses confirmed the successful deposition of NiO on the CF surface. The modification enhanced both the conductivity and capacitance of the electrode and increased the number of microbial attachment sites on the carbon fiber filaments. The prepared CF–NiO electrode was employed as the anode in an MFC, and its electrochemical and energy storage performance were evaluated. The maximum power density of the MFC with the CF–NiO anode reached 0.22 W/m2, compared to 0.08 W/m2 for the unmodified CF anode. Under the C1000-D1000 condition, the charge storage capacity and total charge output of the CF–NiO anode were 1290.03 C/m2 and 14,150.03 C/m2, respectively, which are significantly higher than the 452.9 C/m2 and 6742.67 C/m2 observed for the CF anode. These results indicate notable improvements in both power generation and energy storage performance. High-throughput gene sequencing of the anodic biofilm following MFC acclimation revealed that the CF–NiO anode surface hosted a higher proportion of electroactive bacteria. This suggests that the NiO modification enhances the biodegradation of organic matter and improves electricity generation efficiency.
Biraj Kumar Kakati, Avijit Ghosh, Anil Verma
ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology · 2010
Composite bipolar plates for polymer electrolyte membrane fuel cell (PEMFC) were developed by compression molding technique using vinyl ester resin as a binder and natural graphite, carbon black, and carbon fiber as conductive reinforcements. The developed bipolar plates were characterized for electrical conductivity, flexural strength, deflection at mid-span, hydrogen permeability, and morphology. The in-plane and through-plane electrical conductivities of the composite bipolar plate (VER:25%;CB:5%;CF:5%;NG:65%) were 355.05 and 95.96 S·cm−1, respectively. The flexural strength of the same bipolar plate was 53.50 MPa with a deflection of 5.37%. The hydrogen permeability of the bipolar plate was in the order of 10−9 cm3·cm−1·s−1 at 50°C. The overall properties of the composite bipolar plate were found to achieve the benchmark set by USA-Department of Energy. However, the through-plane electrical conductivity of the above composite was edge below the target value. Therefore, graphene, being one of the most electrical conductive materials, has been reinforced into the composite bipolar plate. The results were very encouraging as 1% graphene reinforcement increased the in-plane and through-plane electrical conductivities of the bipolar plate by around 6 and 35%, respectively. The performance of a PEMFC was evaluated using the developed bipolar plate in in-situ condition.
Tatyana V. Reshetenko, Guenter Randolf, Madeleine Odgaard et al.
ECS Meeting Abstracts · 2020
The most promising alternative to Platinum Group Metals (PGMs) Oxygen Reduction Reaction (ORR) catalysts for proton exchange membrane fuel cell (PEMFC) applications is a class of electrocatalysts consisting of atomically dispersed transition metals (Fe and Mn) in a matrix of carbon and nitrogen, so called M-N-C materials [1]. Currently, the emerging novel M-N-C materials demonstrated 30% of PGM catalyst activity [1]. Performance of PGM-free electrocatalysts can be improved by increasing density of M-Nx sites or optimizing their accessibility through proper integration into the triple phase catalyst layer in a membrane electrode assembly (MEA). Since overall MEA’s performance depends on properties of all its components: membrane, electrodes and gas diffusion layers (GDL), it is important to understand impact of these materials on PGM-free fuel cell operation. In this work we report effects of membrane thickness on performance of PGM-free PEMFCs using various electrochemical methods and modelling. The commercial, PGM-free electrocatalyst manufactured by Pajarito Powder and marketed as PMF-011904 was used in the present study. Catalyst coated membranes with active area of 23 cm 2 were manufactured by IRD Fuel Cell by their proprietary digital printing method. For this work we used membranes with thickness of 15 (LYT0008), 25 (N211), 125 (N115) and 175 (N117) μm. The cathode PGM-free catalyst loading was 6.0 mg cm -2 , while anode employed Pt/C catalyst with loading of 0.2 mg Pt cm -2 . Freudenberg H23C8 GDLs were applied for both electrodes. Electrochemical evaluation of PGM–free MEAs was performed using a custom test station, designed at the HNEI and characterized by dynamic response time <0.1 s. The anode and cathode were fed with H 2 and O 2 respectively, at constant flow rates of 0.5 slpm at 100% relative humidity and 150 kPa absolute backpressure for both electrodes, and the cell temperature was 80°C. Fig. 1 a) shows a representative SEM image of the MEA cross-section. The cathode thickness was found to be 140-160 μm for all samples. The IV data clearly showed that an increase in the membrane thickness led to an increase of HFR and caused poor performance (Fig. 1 b). The highest performance was achieved for MEAs with thin membranes 15 and 25 μm. At the same time application of thick membrane allowed us to reach the highest ocv values 0.979 V (175 μm) vs 0.929 V (15 μm). The impedance data were analyzed using physics-based model which includes proton and oxygen transport in the cathode layer [2]. The results demonstrated a rapid decay of proton conductivity from 15-18 to 5-10 mS cm -1 at current densities higher than 100 mA cm -2 . Possible mechanism of the observed decay can be attributed to dissolution of Fe-N-C centers and formation of Fe 3+ cations which reduce ionomer conductivity by screening SO 3- groups [3-4]. Due to relatively low proton conductivity and large electrode thickness, the ORR rate is strongly non–uniform through the cathode depth. Our estimates showed that this non-uniformity leads to 2 K overheat of the catalyst layer at the membrane surface. The overheat could induce pressure gradient, pushing liquid water out of the electrode and clearing void pores for gaseous transport of oxygen. This mechanism might explain explosive growth of the cathode oxygen diffusivity (5-7⋅10 -3 cm 2 s -1 ). Detailed analyses of the PGM-free PEMFC performance and its correlation with AC-impedance results will be presented and discussed. Acknowledgments We gratefully acknowledge funding from ONR (N00014-19-1-2159) and DOE EERE (DE-EE0008419). The authors are thankful to T. Carvalho for assisting with SEM. Reference 1. S.T. Thompson, A.R. Wilson, P. Zelenay, D.J. Myers, K.L. More, K.C. Neyerlin, D. Papageorgopoulos, Solid State Ionics 319 , 68-69 (2018). 2. A. Kulikovsky, J. Electroanal. Chem . 669 , 28-34 (2012). 3. T. Reshetenko, G. Randolf, M. Odgaard, B. Zulevi, A. Serov, A. Kulikovsky, J. Electrochem. Soc. 167 , 084501 (2020). 4. T. Reshetenko, A. Serov, A. Kulikovsky, P. Atanassov, J. Electrochem. Soc. 166 , F653-F660 (2019). Figure 1
Kea-Lee Yap, Li-Ngee Ho, Soon-An Ong et al.
IOP Conference Series: Earth and Environmental Science · 2020
Abstract Microbial fuel cell (MFC) is a promising and sustainable technology that has high efficiency to produce renewable energy and treat wastewater simultaneously. The effect of carbon materials on the removal of synthetic wastewater in the anodic chamber and electricity generation were investigated using a double chambered MFC. In this study, a double chambered reactor made up of anodic and cathodic chambers separated by proton exchange membrane has been developed. Carbon plate and carbon felt were characterized using scanning electron microscopy. Results revealed that 1.20 times higher chemical oxygen demand removal of synthetic wastewater using carbon felt (50.90%) as compared with that of carbon plate (43.52%). The maximum voltage output produced by carbon felt (280.20 mV) was 20.70% higher than carbon plate (222.20 mV) as cathode in MFC. The surface morphology of carbon materials has significant effect on the oxygen reduction reaction reactivity at cathodic chamber.
Changman Kim, Jung Rae Kim, Jinhee Heo
Journal of Chemical Technology & Biotechnology · 2019
Abstract BACKGROUND Microbial fuel cells (MFCs) are promising devices that can be used to generate electricity from organic wastewater through microbial redox reactions. Various strategies have been attempted to improve the power generation of MFCs, including electrode modification. Titanium (Ti) is a biocompatible metal which is commonly used in various applications. This study examined the improvement of voltage generation by Ti nanoparticle attachment to the carbon electrode surface of an MFC by simple dipping and e‐beam evaporation. Two microbes, namely Shewanella oneidensis MR‐1 and Klebsiella pneumoniae L17, having different electron transfer mechanisms were used to identify the effects of Ti nanoparticles on bioelectricity generation. RESULTS Voltage generation was significantly increased for the MFCs containing Ti nanoparticles, both using S. oneidensis MR‐1 and K. pneumoniae L17. Higher concentrations of DNA extracted from the electrode surface indicated that the Ti nanoparticles did not only assist the electron transfer process from the bacteria to the electrode but also microbial attachment on the carbon electrode. Energy‐dispersive X‐ray spectroscopy (EDS) experiments demonstrated the sustainability of the Ti nanoparticles, showing no significant changes in the attached Ti nanoparticles during an operation period of 3 weeks. CONCLUSION It was demonstrated that the Ti‐dipping method is applicable to MFCs as an electrode modification strategy by Ti nanoparticle formation, leading to a similar level of voltage generation (but through a much simpler process) as compared with conventional evaporation methods. © 2019 Society of Chemical Industry